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CVE-2026-54898PATCHED
rubygems · oj

Oj: Use-After-Free in Oj::Parser SAJ Callback via Input Mutation

Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2,Oj::Parser#parse is vulnerable to a heap use-after-free when a SAJ/SAJ2 callback mutates the input JSON string during parsing. The C engine holds a raw const byte * pointer into the Ruby string's internal buffer. If a callback (e.g. hash_start) resizes the string — for example by calling String#replace with a longer value — Ruby reallocates the string buffer and frees the old one. The C parser's pointer is left dangling; the next character read at parser.c:607 is a use-after-free. This issue has been fixed in version 3.17.2.

Affected Products

VendorProductVersions
rubygemsoj< 3.17.2

References

  • https://github.com/ohler55/oj/security/advisories/GHSA-q2gm-54r6-8fwm(x_refsource_CONFIRM)

Related News (2 articles)

Tier B
CERT-FR3d ago
Multiples vulnérabilités dans les produits IBM (31 juillet 2026)
→ No new info (linked only)
Tier C
VulDB33d ago
CVE-2026-54898 | ohler55 oj up to 3.17.1 parser.c Oj::Parser#parse use after free (GHSA-q2gm-54r6-8fwm)
→ No new info (linked only)
CISA KEV❌ No
Actively exploited❌ No
Patch available
oj@3.17.3
CWECWE-416
PublishedJun 19, 2026
Last enriched33d agov2
Tags
GHSA-q2gm-54r6-8fwmrubygems
Trending Score25
Source articles2
Independent2
Info Completeness8/14
Missing: cvss, epss, kev, exploit, iocs, mitre_attack

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Related CVEs (5)

NONECVE-2026-66066
Action Pack: Possible arbitrary file read and remote code execution in Active Storage variant processing
Trending: 74
MEDIUMCVE-2026-54500
Oj: intern.c form_attr has an uninitialized stack read
Trending: 28
NONECVE-2026-54899
Oj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle
Trending: 25
NONECVE-2026-54897
Oj : Use-After-Free in Oj::Doc Iterators via Reentrant Close
Trending: 25
NONECVE-2026-54896
Oj: Heap Buffer Overflow in Oj.dump Exception Serialization via Large Indent
Trending: 25

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Verification

State: unverified
Confidence: 0%

Vulnerability Timeline

CVE Published
Jun 19, 2026
Discovered by ZDM
Jun 19, 2026
Updated: description, affectedVersions, severity
Jul 1, 2026
Patch Available
Jul 1, 2026

Version History

v2
Last enriched 33d ago
v2Tier C33d ago

Updated vendor to ohler55, product to oj, severity to CRITICAL, and affected versions to < 3.17.1, while also providing a new description.

descriptionaffectedVersionsseverity
via VulDB
v144d ago

Initial creation